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Three men were severely burned on Thursday after a concentrated cannabis extraction lab exploded in a storage container in Phelan. A version of this report aired during the NBC4 News at 5 p.m. on Sept. 27, 2013. (Published Friday, Sep 27, 2013)

Updated at 8:44 AM PDT on Saturday, Sep 28, 2013

Three men suffered serious burns in what investigators said was a marijuana lab explosion in Phelan, located in Southern California, on Thursday.

The men were in a white storage container when the blast took place, sheriff's investigators said. They suffered first- and second-degree burns all over their body.

Investigators said near 1,200 butane fuel canisters littered on the high-desert property indicated that the structure was being used as a concentrated cannabis extraction lab, which they said was as dangerous as a methamphetamine lab.

"It is highly explosive because of the butane that is being used to extract the THC," said Jodi Miller, spokeswoman for the San Bernardino County Sheriff's Department.

There have been at least two other large cannabis lab explosions in Southern California this year.

In July, two men were severely burned when a lab exploded inside a Tustin garage.

Three people were also injured in a lab blast inside a San Diego hotel room in January.

A narcotics task force has discovered at least 20 cannabis labs in San Bernardino County, many of them in heavily populated residential neighborhoods, investigators said.

"Not only are they putting themselves in danger, they are putting surrounding neighbors in danger," Miller said.

The men who were injured Thursday were recovering at an area burn center. Investigators said they will be arrested and face criminal charges once they are released from the hospital.